Method for constituting a home automation network

ABSTRACT

A method of constituting a home automation network comprises bidirectional elements such as actuators (A 1 , A 2 , A 3 ), at least unidirectional control elements (C 1 , C 2 , C 3 , S 1 ) and bidirectional control elements (C 60 , C 70 , C 800 ). It consists in lastingly functionally linking up at least two elements. The process is characterized in that the lasting functional linkup brings about at least one transfer from a bidirectional element to another bidirectional element of at least one information creating a hierarchical relationship between these two elements.

FIELD OF THE INVENTION

The invention relates to the field of home automation networks and moreparticularly to a method of constituting an individual network or anetwork comprising an association of individual networks, said networkallowing communication between products intended for the management ofsecurity or comfort inside a building, and particularly in the home,when these products communicate via a non-wired link, and particularlyby radio waves.

In the field of home automation or of the technical management ofbuildings, installations are already known that associate differentcomponents such as blinds, rolling shutters, gates and all other devicessuch as air conditioners or means of heating or lighting. Users, who arebecoming increasingly demanding, have caused the technique of managingthe different components to progress, and the manufacturers, in order tosatisfy the clientele, have set up installations in home automationnetwork form comprising management means.

The problems remaining to be solved are those due to the installation ofthe various components that are actuated by actuators, controlled bytransmitters, sensors or all other control devices. In effect, theinstaller very frequently has to constitute the network withoutparticular knowledge and must also ensure that new equipment elementsare recognized and must constitute new groups of products in an existinginstallation, all in the simplest manner, without, for all that, knowingthe sophisticated techniques of implementation.

BACKGROUND OF THE INVENTION

Already known are installations according to which the functional linkupallows two specific elements of the network to share, temporarily orpermanently, a link of communication. This link allows, for example, afirst element, to obey the instructions sent by a second element. Thelink here being called “temporary” when the link can be re-examinedduring an intentional reconfiguration of the network requiring anintervention by a person skilled in the art or by a knowledgeable user.

There are several manners, known to those skilled in the art, of sharingsuch a link.

For wired versions, developed through proprietary networks, and thenshared, a configuration phase allows the installer to make the desiredpairings and above all groupings. American patent U.S. Pat. No.5,544,037 describes such a mode of defining group addresses in thelighting field. In the case of shared networks, of the Echelon(registered trademark) type, more intuitive methods of linkup areproposed. Such methods have been divulged notably by American patentU.S. Pat. No. 4,918,690 and European patents EP 0 838 740 and EP 0 574636.

Through American patents U.S. Pat. No. 4,689,786 and U.S. Pat. No.4,847,834 and through European patent EP 0 629 934, methods are known bywhich, to simplify the linkup, the physical identity of each networkcomponent usually gives way to a logical identity, for example, a serialnumber incremented each time a component is inserted into the local areanetwork (LAN).

Concerning the linkup of systems communicating by radio waves, anadditional difficulty arises because there is no wired link making itpossible to distinguish clearly between what belongs to the network andwhat belongs to the outside, and this demands an increase in the levelof security.

In the most simple cases as divulged by patents U.S. Pat. No. 4,385,296and U.S. Pat. No. 4,750,118, a learning procedure allows the receiver ofan element to place in memory an identification code contained in thetransmitter of the other element, or vice versa.

Also described in the prior art are cloning methods, used to reproducefrom one transmitter to the other a single code or a plurality ofidentification codes already known to one or more receivers. Thisreproduction may take place directly between said transmitters by meansof a temporary wired link as in European patent EP 0 533 623 andAmerican patent U.S. Pat. No. 6,020,829, or again directly between saidtransmitters by radio waves, one of the transmitters being in factbidirectional as divulged in document U.S. Pat. No. 4,988,992.

The identification code may consist of a physical address or a logicaladdress and may be encrypted during the learning transmission. The knownmethods of “rolling code” or of “code hopping” can be used to avoiddirectly transmitting the image of the identification code. In the bestprotected links, the identification code is itself totally variable andis simply a “seed” used by an algorithm of the receiver that allows thelatter to predict the next value or values of the identification code.Only the seed is then transmitted during the learning procedure, asdescribed in patent U.S. Pat. No. 6,191,701.

In the specifications of the Bluetooth (registered trademark) typenetwork, the establishment of a link is achieved by the memorization ofa common key, created and exchanged during a pairing procedure betweentwo elements. As in the case of linkups of wired networks of the Echelon(registered trademark) type, the installer presses a specific button todesignate each element intended to be tied up.

Further removed from networks, but sharing the authentication problem,the field of electronic locks has given rise to implementations in whichthe learning of a new control element (user-key) by an actuator element(lock) is performed under the supervision of a third element(master-key). This third element is not itself authenticated during alearning procedure but by a code pre-registered in the actuator elementduring its manufacture as described by the international patentapplication published under number WO 80/02711.

Also found, notably in French patent 2 761 183, in the field of remotedoor controls, is a form of authentication, during a functional linkup,performed by a transmitter which itself has been previously registeredduring a learning procedure. But this patent, filed by the applicant,does not provide for this step to be used to communicate, inbidirectional manner, the information necessary for the progressiveimplementation of a network.

Also known from patent U.S. Pat. No. 5,844,888 is a method ofimplementing a network comprising identical individual cellscommunicating with one another in bidirectional manner. Each cellreceives an identifier during its manufacture. A cell grouping device isused to access the identifier specific to each cell and to group thecells by assigning a group identifier to them. When the network has beeninstalled, the cells can group together themselves. This grouping isbased on the sharing, between the cells, of a group identifier. Thesending of identifiers is used to determine which cells aretransmitters, which cells are receivers and which cells are transmissionrelays.

From patent U.S. Pat. No. 5,420,572, a device for configuring acommunication network is known. This device comprises means allowing itto connect itself temporarily to the elements constituting thecommunication network in order to transfer information for use inconstituting the latter.

All the prior art is therefore dedicated:

either to devices intended to function in univocal manner (severaltransmitters, one receiver) even in the case of possible bidirectionallinks (then simply intended for acknowledgement transmission by thereceiver to the transmitters),

or to devices communicating in a network and placed on a level ofequality, without hierarchical structuring of said network,

or to devices communicating in a network, in structured manner, after atleast one phase of configuration in which the installer (or thecompetent user) has designated all the links and groups.

The prior art therefore does not resolve the problem of cohabitation ina home automation network of both unidirectional and bidirectionaldevices.

The prior art does not allow the setting up of a network installationaccording to modalities that are strictly identical (for the installer)to those used in the case of the univocal devices to which he isaccustomed.

The prior art describes, in the patent of the applicant published undernumber 2 761 183, a type of functional linkup of two elements, carriedout under the supervision of a third element, itself previouslyauthenticated with one of the elements during a learning operation, butwithout these elements being bidirectional and furthermore without thislinkup causing the transfer by a first bidirectional element to a secondbidirectional element of at least one information structuring thenetwork.

The prior art does not provide for:

-   -   the information hierarchically structuring the network to be a        group name,    -   the information hierarchically structuring the network to be the        identity of the links already established with the first        bidirectional element.

SUMMARY OF THE INVENTION

Thus, according to the invention, the method of constituting a homeautomation network, comprising bidirectional elements such as actuators,control elements which are at least unidirectional (transmitters,sensors), bidirectional control elements, is of the type which consistsin lastingly functionally linking up at least two elements, and ischaracterized in that the lasting functional linkup brings about atleast one transfer from a bidirectional element to another bidirectionalelement of at least one information creating a hierarchical relationshipbetween these two elements.

According to an additional feature, the information creating ahierarchical relationship between these two elements comprises a groupname.

According to another additional feature, the information creating ahierarchical relationship between these two elements comprises theidentity of the links already established with the element sending theinformation.

Additionally, the method according to the invention can be such that thelasting functional linkup between two bidirectional elements is achievedunder the supervision of a third element which is itself previouslyauthenticated at one of the elements during a learning operation. Thisis particularly valuable when one of the bidirectional elements isdifficult to access.

According to one of the embodiments, the functional linking up of abidirectional control element with a bidirectional element is achievedunder the supervision of an at least unidirectional control element.

According to other embodiments,

the functional linking up of an at least unidirectional control elementwith a bidirectional element is performed under the supervision of abidirectional control element,

the functional linking up of two bidirectional control elements of thesame hierarchical level is ensured by the linking up of each of thebidirectional control elements with a control element of higherhierarchical level,

the functional linking up of two bidirectional elements is ensured bythe successive functional linking up of each of them with one and thesame bidirectional control element,

during a functional linking up of a bidirectional control element withanother element, the latter communicates to said bidirectional controlelement the set of identifiers relating to the elements with which it isalready linked up,

during a functional linking up between two control elements of differenthierarchical levels, the transmission of information providing thepreestablished relationships takes place from the lower level element tothe higher level element,

during a functional linking up of a bidirectional control element withanother element, a group name is transferred that becomes common to allthe lower level elements linked up with said bidirectional controlelement,

the transmission of the group name can be coded according to anencryption algorithm: for example, the group name is not directlytransmitted as such but in the form of a “seed” allowing the group nameto be reconstructed by each element containing one and the samedecryption polynomial.

The invention allows control or other unidirectional elements to cohabitin one and the same home automation network with bidirectional elements.

Amongst other things, it allows the network to be constitutedprogressively, in space and in time, while protecting this constitution,particularly against the intrusion of foreign elements and/or againstthe involuntary addressing of elements not belonging to the network.

In particular the invention makes it possible for no changes to be madeto the way the installer does things, when he first and individuallyassociates the simple control points with the actuators to becontrolled, before proceeding to associate the general control point orpoints with said actuators, and allows a more direct method of pairingwhen the installer has a supervision set.

An important advantage of the invention is also that it permits theconstitution of a network containing at least several elements on whichno direct physical action of the installer is possible in orderexplicitly to designate the product or products to be linked up.

BRIEF DESCRIPTION OF THE DRAWING

The invention will be more easily understood through the description ofa preferred embodiment, allowing the progressive and implicitconstitution of the network.

Other features and advantages of the invention will emerge from thefollowing description relating to the appended drawing.

FIG. 1 is a diagram of a network to which the method according to theinvention applies.

DETAILED DESCRIPTION

The communication network which is illustrated as an example in FIG. 1comprises a partial or total combination of bidirectional elementsassociated with actuators and/or sensors, unidirectional elementsassociated with sensors, unidirectional elements associated with remotecontrols, bidirectional elements associated with remote controls towhich a first hierarchical level is attributed and, finally,bidirectional elements associated with functions of remote control andof supervision with which a higher hierarchical level is associated. Thehierarchical level of a bidirectional element is preferentially definedby the manufacturer and is mentioned in the communication frame.

Physical communication between elements of the network functionspreferentially according to a multi-master/multi-slave mode.

FIG. 1 shows an example of a network comprising a set of actuators (A1,A2, A3), controls (C1, C3), a sensor (S1), placed in one and the samebuilding. The actuators (A1, A2, A3) are radio controlled. They maythemselves incorporate specific sensors, for example position, pressureor obstacle sensors. For simplification purposes, they are howeverdesignated by the single term “actuators”. Placed inside the productsthey drive, the actuators are not directly accessible other than by abutton or are quite simply difficult to access.

The installation of the products in FIG. 1 has been completed, forexample, in several phases.

In a first installation phase, a terrace blind (B1) incorporating afirst bidirectional actuator (A1) has been put in place, as has a firstunidirectional wind-sun weather sensor (S1), intended for the automaticdriving of the actuator (A1), which is provided also to be controlleddirectly by the user, by means of a first unidirectional radio control(C1).

The installer will first have to pair up the first radio control (C1)with the first actuator (A1) in a conventional manner, by using, forexample, the so-called programming button disposed on the control, and aproperty of the actuators not yet paired (blank) to accept any pairingcommand, as described in the prior art. This first pairing isrepresented in FIG. 1 by the arrow (F1).

Thereafter, the first actuator (A1) does not accept any new pairingcommand unless it comes from a control that it already knows. Forexample, the pairing of the sensor (S1) with the first actuator (A1)will be performed by the installer under the supervision of the firstcontrol (C1). By pressing the programming button of the first control(C1), the installer uses this first control (C1) to transmit a learningrequest to the first actuator (A1), thus validating the acquisition bysaid first actuator (A1) of the next code transmitted. The installerthen presses the programming control of the first sensor (S1). Theidentification of the first sensor (S1) is then registered by the firstactuator (A1). This method is used to register several identifiers ofthe various controls in one and the same actuator. This second pairingis represented in FIG. 1 by the arrow (F2).

It will be noted that at this stage the bidirectional character of thefirst actuator (A1) is not yet used.

By pursuing the same example, the building experiences thereafter asecond installation phase, with the putting in place of two rollingshutters (B2, B3) each incorporating an actuator (A2, A3), that is tosay a second bidirectional actuator (A2), controlled by a firstunidirectional control (C2) for the first rolling shutter (B2) and athird bidirectional actuator (A3) controlled by a third unidirectionalcontrol (C3) for the second rolling shutter (B3). The pairing of thesecond control (C2) with the second actuator (A2) and of the thirdcontrol (C3) with the third actuator (A3) is performed as previously, bysuccessive operations represented in FIG. 1 by the arrows (F3) and (F4).

At this stage, the bidirectional character of the second and thirdactuators (A2, A3) has as yet not been used.

However, another pairing procedure is possible for these two actuators(A2, A3), which use a previous communication method (represented by thearrow (F5)) between products not yet paired (blank).

This previous communication mode consists in that the newly connectedblank products establish in standalone manner an order relationship bywhich they do not all react simultaneously to a command from theinstaller, and thus facilitating the individual pairing of the products.Such a method could just as well have been used here prior to thepairing of the second and third controls (C2, C3). The provisionalbidirectional communication represented by the double arrow (F5)established on this occasion relates only to the blank products andcould not be likened to the network construction described here, the aimof which is to establish lasting links between elements.

At this stage of the installation, it is, for example, decided forreasons of convenience, that the second control (C2) may also controlthe second rolling shutter normally activated by the third actuator(A3). The installer must therefore see to it that this third actuator(A3) learns to recognize the instructions of the second control (C2).This operation, represented by the arrow (F6) is performed under thesupervision of the third control (C3), exactly as the first actuator(A1) learned to recognize the instructions of the first sensor (S1)under the supervision of the first control (C1).

Thereafter, it is decided to add to the installation a first generalbidirectional control (C60), in order to constitute the network of theinvention.

Exactly as he does it with the products of the prior art, the installerwill necessarily have to see to it that the different actuators learnthis new control. This takes the form of three successive pairingoperations, represented in FIG. 1 by the arrows (F10, F11, F12). Theseoperations are carried out respectively under the supervision of thefirst control (C1), of the second control (C2) and then the thirdcontrol (C3).

According to the invention, this pairing step is used to transmit atleast one of the following information:

the list of elements, already known to the actuators (A1, A2, A3), thatis to say the controls (C1, C2, C3) and the sensor (S1).

a group name, which will be common to all the elements paired with thisbidirectional control.

Advantageously, this group name originates, for example, from theidentification number of the bidirectional control and, in this case, itwill always be transmitted from that control to the elements with whichthat control is paired thereafter. It is nevertheless preferable in somecases for the group name, on the contrary, to originate from the firstactuator (or element) paired with this bidirectional control. In thiscase, the group name will first of all be transmitted to thebidirectional control during the first pairing which, in turn,communicates it to the other elements during subsequent pairings.

This will be illustrated based on the installation in FIG. 1. During thelinking up (F10) of the first actuator (A1) and of the first generalcontrol (C60), under the cover of the first control (C1), the firstactuator (A1) transmits to said first general control (C60) theidentifiers that it knows, that is to say the first control (C1) and thesensor (S1). Likewise, during the linking up (F11) between the secondactuator (A2) and said first general control (C60), under cover of thesecond control (C2), the second actuator (A2) transmits to the firstgeneral control (C60) the identifier that it knows, that is to say thesecond control (C2), and finally, during the linking up (F12) of thethird actuator (A3) with the first general control (C60), under cover ofthe third control (C3), the third actuator (A3) transmits to the firstgeneral control (C60) the identifiers of the second and third controls(C2, C3).

Clearly these operations are carried out in any order.

It is proposed to profit from this first linkup to transfersimultaneously and automatically a common identifier serving as groupname to the network now constituted, implicitly, by these successivelinkups. The group name (NG1) is advantageously constructed based on theidentifier of the first general control (C60). All the actuators, thatis to say the first, the second and the third actuators (A1, A2, A3),then know that they are part of the same group (NG1).

This has the effect of:

allowing the relaying (repetition, routing) where appropriate by anybidirectional actuator (A1, A2, A3) of the network NG of any messagesensed by one of the actuators that is not the intended recipient ofsaid message and for which it establishes that the intended recipienthas not sent an acknowledgement. This process known elsewhere, givingthe network significant “robustness”, allows:

operation in low activity/low consumption mode of all the actuators, thelatter pursuing each frame sensing only if the latter has begun with thenetwork identifier,

reaction to a collective polling mode concerning the members of thenetwork only.

As such, it is entirely possible to use the invention in a differentchronology from that which has just been proposed. Thus, during each ofthe first linkups (F10, F11, F12), only the group name NG1 istransmitted. It would then be only during a succession of subsequentindividual polls, or better during a collective poll, carried out by thefirst general control (C60), that the identifiers known to each actuator(A1, A2, A3) would be transmitted to this control (C60).

After this operation, the first general control (C60) therefore has atable, preferentially structured, giving the topology of the group(NG1), as follows:

NG1 - C60 A1 C1 S1 A2 C2 A3 C3 C2

The value of ensuring that the identifiers known to each actuator (ormore generally to each bidirectional element) automatically uploaded tothe general control (C60) can be easily understood from a singleexample: it is known that rolling shutters can very effectivelycontribute to light management or to protecting the interior againstoverheating from the sun. Thus, the information given by the sensor (S1)initially attached functionally to the single first actuator (A1)becomes available for the general control (C60) and usable if the lattercontains a solar management program, or even directly for all theequipment elements in the group (NG1) which activate such a programpreviously registered or downloaded after installation.

In parallel with the previous installation, concerning the mobileproducts of the building, one can imagine having to install other radiocontrolled products using one and the same protocol, shared betweenseveral specialisms. It would involve, for example, lighting systems(B4) or heating and air conditioning systems (B5), not shown, fittedwith actuators, respectively, a fourth actuator (A4) and a fifthactuator (A5), controlled respectively by a fourth control (C4) and afifth control (C5), and even a second sensor (S2), these also not beingshown.

These other systems are in turn controlled by at least one secondgeneral bidirectional control (C70). These systems constitute anotherindependent network (NG2). The table in the second general control (C70)contains, as previously, the (structured) list of all the identifiers ofthe group NG2. Suppose, for example, that the second general control(C70) contains the identifiers of the two actuators, that is to say ofthe fourth actuator (A4) and of the fifth actuator (A5) in turncontrolled by their corresponding controls (C4) and (C5), and also bythe second sensor (S2).

In a new installation phase, an additional bidirectional control (C800)of a higher hierarchical level than the first and second generalcontrols, respectively (C60, C70), is installed. This additional generalcontrol is, for example, a centralized control furnished with comfortmanagement programs requiring the interaction of products of differentspecialisms.

Note that, this time, a direct pairing of the additional general control(C800) with the first general control (C60) or with the second generalcontrol (C70) is possible, since this type of product can be accesseddirectly by the installer and possesses, for example, a learningdesignation or initiation button. The pairing therefore is no longernecessarily done under the supervision of a third, previouslyauthenticated, component.

On the other hand, each of these pairing operations will take place,according to the invention, on an information transfer.

For example, the additional control (C800) transmits its group name(NG3) to the first general control (C60), while this general control(C60) transmits its group name (NG1) to the additional control (C800).Likewise, the group names (NG2 and NG3) are exchanged between theadditional control (C800) and the second general control (C70).

During the same operation, or in deferred manner, the identifiersincluded in each table are also transmitted.

Thus, the table included in the additional control (C800) may appearstructured as follows:

NG3 - C800: NG1 - C60 A1 C1 S1 A2 C2 A3 C3 C2 NG2 - C70 A4 C4 A5 C5 S2

The first general control (C60) and the second general control (C70) nowknow that they belong to one and the same set (NG3) and may, whereappropriate, propagate this information to the elements they supervise.

It can be seen that, although communication between elements of thenetwork may take place in any manner and, for example, inmulti-master/multi-slave form, the network is functionally structured bythe very way in which it is constituted.

It has been understood that lasting functional linkup meant that, untilthere is a new intervention in the installation, a first element becomescapable of sending orders or information to a second element capable ofreceiving, interpreting or executing them.

Additionally, several complementary or mutually exclusive embodimentscan be used:

1. The functional linking up of a bidirectional control (C60) with abidirectional actuator (A1, A2, A3) is performed under the supervisionof a unidirectional control element (C1, C2, C3).

2. The functional linking up of an at least unidirectional controlelement (C1, C2, C3) or of an at least unidirectional sensor (S1) with abidirectional sensor-actuator element (A1, A2, A3) is performed underthe supervision of a bidirectional control (C60).

3. The functional linking up of two bidirectional controls (C60, C70) ofthe same hierarchical level is ensured by the linking up of each of thebidirectional controls with a control of higher hierarchical level(C800).

4. The functional linking up of two bidirectional sensor-actuators (A1,A2, A3) is ensured by the successive linking up of each of them with oneand the same bidirectional control (C60).

5. During a functional linking up of a bidirectional control (C60, C70or C800) with one of the elements, the latter communicates to saidbidirectional control the set of identifiers relating to the controlswith which it is already linked up.

6. In the case of a linking up between two controls of differenthierarchical level, the transmission of information on thepreestablished relations takes place from the lower level element to thehigher level element.

7. During a functional linking up of a bidirectional control (C60, C70or C800) with one of the elements, a group name NG is transferred thatis common to all the lower level elements linked up with saidbidirectional control unit.

8. The transmission of the group name NG is coded according to anencryption algorithm. For example, the group name is not directlytransmitted as such but in the form of a “seed” allowing the group nameto be reconstituted by each element containing one and the samedecryption polynomial.

It has been seen, in the network given as an example, that the first,the second and the third control (C1, C2, C3) are unidirectionalelements, but this does not have to be the case, because the one or theother, or even the totality of the controls, may be of the bidirectionaltype, if only for transferring an acknowledgement, for example.

The description does not mention the subsequent update procedures,during a pairing of new elements in the network that is alreadyconstituted, these procedures being within the capabilities of thoseskilled in the art.

Naturally, the invention is not restricted to the embodiments describedand represented as examples, but it also includes all the technicalequivalents and their combinations.

1. A method of constituting a home automation network, comprising bidirectional elements such as actuators, control elements which are at least unidirectional, bidirectional control elements, which include in lastingly functionally linking up at least two elements, wherein said lastingly functionally linking up of said at least two elements brings about at least one transfer from a bidirectional element to another bidirectional element of at least one information creating a hierarchical relationship between said two elements.
 2. The method of constituting a home automation network, as claimed in claim 1, wherein the information creating a hierarchical relationship between said two elements includes a group name.
 3. The method of constituting a home automation network, as claimed in claim 2, wherein a transmission of the group name is coded according to an encryption algorithm.
 4. The method of constituting a home automation network, as claimed in claim 1, wherein the information creating a hierarchical relationship between said two elements comprises an identity of the links already established with the element sending the information.
 5. The method of constituting a home automation network, as claimed in claim 1, wherein the lasting functional linkup between two bidirectional elements is achieved under the supervision of a third element which is itself previously authenticated at one of the elements during a learning operation.
 6. The method of constituting a home automation network, as claimed in claim 1, wherein the functional linking up of a bidirectional control element with a bidirectional element is performed under the supervision of an at least unidirectional control element.
 7. The method of constituting a home automation network, as claimed in claim 1, wherein the functional linking up of an at least unidirectional control element with a bidirectional element is performed under the supervision of a bidirectional control element.
 8. The method of constituting a home automation network, as claimed in claim 1, wherein the functional linking up of two bidirectional control elements of the same hierarchical level is ensured by the linking up of each of the bidirectional control elements with a control element of higher hierarchical level.
 9. The method of constituting a home automation network, as claimed in claim 1, wherein the functional linking up of two bidirectional elements is ensured by the successive functional linking up of each of the bidirectional elements with one and the same bidirectional control element.
 10. The method of constituting a home automation network, as claimed in claim 1, wherein, during a functional linking up of a bidirectional control element with another element, said another element communicates to said bidirectional control element a set of identifiers relating to the elements with which it is already linked up.
 11. The method of constituting a home automation network, as claimed in claim 1, wherein, during a functional linking up between two control elements of different hierarchical level, the transmission of information regarding preestablished relationships takes place from an element of a lower level to an element of a higher level.
 12. The method of constituting a home automation network, as claimed claim 2, wherein, during a functional linking up of a bidirectional control element with another element, there is exchanged a group name becoming common to all the elements of lower level linked up with said bidirectional control element.
 13. The method of constituting a home automation network, as claimed in claim 12, wherein in that the transmission of a group name is coded according to an encryption algorithm. 